State-of-the-art video coding schemes, such as MPEG-4 AVC/H.264, and the upcoming HEVC (High-Efficiency Video Coding), support coding of image and video contents comprising one or more color planes/components. An example of such video contents is video data in YUV color space with 4:2:0 chroma format (color plane format). YUV color space comprises one luminance plane (Y) and two chrominance planes (U and V), while 4:2:0 chroma format indicates that the resolution of the two chrominance planes is horizontally and vertically half of the luminance plane resolution. Some examples of the commonly used color plane formats are illustrated in FIG. 1.
At aligned positions (as illustrated in FIG. 2), different color planes of an image often contain object shapes and features that are correlated or similar to a certain extent. By utilizing such a correlation, inter-color-plane prediction can be performed in which samples of a second color plane (such as the U plane) are predicted from prior reconstructed samples of a first color plane (such as the Y plane). During both encoding and decoding processes, reconstruction of a first block of the first color plane is performed prior to the prediction process for an aligned second block of the second color plane, so that reconstructed samples of the first block are available for generating the prediction samples for the second block. Inter-color-plane prediction is supported in the Working Draft 3 of HEVC video coding scheme.